Permanent structures in liquid metal fast breeders such as reactor vessel, shield and grid are irradiated up to 823 K to low dose neutron fluences up to 5 × 1025n.m−2 (E > 0.1 MeV). Such large components are built from different heats with variations in chemical compositions and thermo-mechanical treatment. This paper reports the determination of the low dose irradiation effects on the resulting heat-to-heat variation of DIN 1.4948 stainless steel (similar to AISI Type 304) creep and tensile properties. The variation in ultimate tensile strength of six heats of plate and forgings is unaffected by irradiation. Both tensile and creep strength are reduced by irradiation due to a decrease in ductility. Post-irradiation strengths of three types of welded joints are equal to those of the parent metal they are connecting. The irradiation effect is attributed to helium enhanced intergranular crack growth. The 10,000 h creep strength of 823 K and 873 K can be predicted from the ultimate tensile strength of the particular heat or welded joint in unirradiated and irradiated condition. The combination of variability and reduction in creep strength by irradiation can be accounted for by appropriate strength reduction or rupture life reduction factors.